1. Field of the Invention
This invention relates generally to internal combustion engines, and more specifically to an integrated air induction module for a gasoline engine.
2. Background Information
Spark-ignited, fuel-injected internal combustion engines enjoy extensive usage as the powerplants of automotive vehicles. In a representative piston engine, an intake manifold conveys intake air to intake valves of engine combustion cylinders. The intake valves are normally closed but open at certain times during the operating cycle of each cylinder. Pistons that reciprocate within the engine cylinders are coupled by connecting rods to a crankshaft. When the normally closed intake valves open, fuel, such as gasoline, is sprayed by electric-operated fuel injectors into intake air entering the cylinders, creating charges of combustion gases that pass through the open intake valves and into the combustion cylinders. After the intake valves close, the charges are compressed by the pistons during compression strokes and then ignited by electric sparks at the beginning of power strokes to thereby drive the pistons and power the engine.
Various air intake arrangements are documented in patent literature. A known air intake system for an engine comprises a succession of components that run in series, beginning at a dirty air inlet, and ending at the engine. Dirty air is conveyed through a dirty air duct to an air box. A particulate filter within the air box filters certain particulate material from the intake air flow so that clean air emerges from the air box. That clean air passes through a throttle that operates to selectively restrict the flow. From there the flow passes to a plenum, and thence through individual tracts, or runners, leading to the individual engine cylinders.
Developments in materials and processes have enabled various parts of engine air intake systems to be fabricated in ways that significantly differ from metal casting and machining methods that have been used in the past. The ability to fabricate intake system parts using newer processes and materials offers a number of benefits, including for example and without limitation: opportunities to structure intake systems in novel configurations for design and/or functional purposes; realization of fabrication and assembly cost savings; shorter lead times from design to production; and more efficient use of engine compartment space in an automotive vehicle. Productivity improvements in the manufacture of engine air intake systems may be attained through increased integration of individual component parts. A total integration of individual components would provide an intake system module that could be tested by itself before assembly to an engine, and then assembled as a unit to the engine. Fabrication and testing of modules could be performed by a supplier before shipment to an engine assembly plant, or a motor vehicle assembly plant, where modules would be assembled directly to engines. Even if it were not feasible to fabricate a total module, the integration of a substantial number of its constituents would be advantageous.
There are different configurations for injecting fuel into gasoline engines. In a port-injected engine, fuel injectors are disposed relatively more inclined to the length of a cylinder, generally to the side of the cylinder. In a direct-injection engine, fuel injectors are disposed relatively less inclined and poised at the top of a cylinder. Accordingly, different considerations are apt to be present of the design of intake systems for the respective engine configurations.
An example of a known module appears in U.S. Pat. No. 5,713,323 assigned at issue to Ford Motor Company. A commonly owned patent application Ser. No. 09/329,724, filed Jun. 10, 1999 also relates to an integrated air induction module for gasoline engines.